Comparison of reproductive performance of Black Sea salmon broodstock (Salmo labrax PALLAS, 1814) reaching first sexual maturity at different ages

Abstract

The aim of this study was to determine the individual first maturation age diversity in hatchery-originated F6 generation of Black Sea salmon (Salmo labrax) broodstock created by applying for a selective breeding program. Research was carried out in freshwater ponds and marine net cage systems between 2018-2021. In the study, 136, 87 and 3 individuals from the broodstocks that reached the first sexual maturity at the age of 22, 34 and 46 months were used, respectively. Total egg production, relative egg production, egg diameter and fertilization rates were determined at the first stripping of broodstock that reached sexual maturity at different ages. The first gonadal development controls and stripping studies were carried out in the period of 2018-2019 for 22 months old broodstock, 2019-2020 for 34 months old and 2020-2021 for 46 months old. Total fecundity of 22, 34 and 46 months old broodstocks that were stripped, were calculated at 1108.98±40.73, 3869.02±138.43 and 5899.52±1143.78 egg/kg broodstock, relative fecundity was 3024.87±87.52, 2291.90±89.52 and 1816.00±284.51 egg/kg broodstock, egg diameters were 4.40±0.01, 5.07±0.02 and 5.35±0.09 mm and fertilization rates were determined as 92.21±0.87%, 95.69±1.65% and 89.83±2.77%, respectively. The condition factor values of the rootstocks were determined as 1.05±0.02 (22 months old), 1.09±0.01 (34 months old) and 1.08±0.03 (46 months old). In the broodstock, individuals with a first maturation age of 22 months have predominantly red spots with a white halo around the perimeter, silvery coloration with black spots at 34 months of age, and silvery coloration with black spots at 46 months of age were detected. While enterprises that reared Black Sea salmon in freshwater and have restaurants prefer the red-spotted river ecotype for production, enterprises that produce in marine net cages prefer the black-spotted-silver-colored marine ecotype, whose body coloration is similar to Atlantic salmon.